1. Field of the Invention
The present invention relates to a positioning device and, more particularly, to an elastically expandable positioning device for positioning a cover of a unified pod during the semiconductor wafer process.
2. Description of Related Art
A gate of a common unified pod loading system has an opening device to open the cover of the unified pod, and two positioning pins positioned at the positions corresponding to two positioning holes on the cover of the unified pod. Therefore, during the opening process, the positioning pins and the positioning holes both assist to position the cover. Prior art design of the positioning device is simply a column-shaped positioning pin. However, due to the consideration of the unified pod manufacturing process, the diameter of said two positioning holes is usually greater 0.5 mm than the diameter of said two positioning pins, which causes the outcome of the position is not satisfied. Consequently, during the opening process the obliquity will occur easily, and then the friction between the cover and the unified pod body will generate powder which causes even more serious abrasion and pollution.
The object of the present invention is to provide an elastically expandable positioning device, which can reduce the obliquity and the abrasion powder between the cover and the unified pod body.
To achieve the object, the positioning device of the present invention includes a central fastener having one end protruded on the interface plate, the central bolt further having an axial input hole opened at another end, and at least one radial distributing hole equally opened at the circular surface;
a ring-shaped inflatable body made from an expandable elastic material;
a supporting ring encircled around the central bolt and positioned above the distributing hole, for supporting the inflatable body, the supporting ring having at least one radial inflating hole equally positioned corresponding to the radial distributing hole of the central bolt; and
an input fluid source connected to the axial input hole of the central bolt, for providing an input fluid.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.